Some devices have problems with Transaction Layer Packets with the RelaxedOrdering Attribute set. This patch set adds a new PCIe Device Flag,PCI_DEV_FLAGS_NO_RELAXED_ORDERING, a set of PCI Quirks to catch some knowndevices with Relaxed Ordering issues, and a use of this new flag by thecxgb4 driver to avoid using Relaxed Ordering with problematic Root ComplexPorts.

It's been years since I've submitted kernel.org patches, I appolgise for thealmost certain submission errors.

v2: Alexander point out that the v1 was only a part of the whole solution, some platform which has some issues could use the new flag to indicate that it is not safe to enable relaxed ordering attribute, then we need to clear the relaxed ordering enable bits in the PCI configuration when initializing the device. So add a new second patch to modify the PCI initialization code to clear the relaxed ordering enable bit in the event that the root complex doesn't want relaxed ordering enabled.

The third patch was base on the v1's second patch and only be changed to query the relaxed ordering enable bit in the PCI configuration space to allow the Chelsio NIC to send TLPs with the relaxed ordering attributes set.

This version didn't plan to drop the defines for Intel Drivers to use the new checking way to enable relaxed ordering because it is not the hardest part of the moment, we could fix it in next patchset when this patches reach the goal.

v3: Redesigned the logic for pci_configure_relaxed_ordering when configuration, If a PCIe device didn't enable the relaxed ordering attribute default, we should not do anything in the PCIe configuration, otherwise we should check if any of the devices above us do not support relaxed ordering by the PCI_DEV_FLAGS_NO_RELAXED_ORDERING flag, then base on the result if we get a return that indicate that the relaxed ordering is not supported we should update our device to disable relaxed ordering in configuration space. If the device above us doesn't exist or isn't the PCIe device, we shouldn't do anything and skip updating relaxed ordering because we are probably running in a guest.

v4: Rename the functions pcie_get_relaxed_ordering and pcie_disable_relaxed_ordering according John's suggestion, and modify the description, use the true/false as the return value.

We shouldn't enable relaxed ordering attribute by the setting in the root complex configuration space for PCIe device, so fix it for cxgb4.

Fix some format issues.

v5: Removed the unnecessary code for some function which only return the bool value, and add the check for VF device.

Make this patch set base on 4.12-rc5.

v6: Fix the logic error in the need to enable the relaxed ordering attribute for cxgb4.

v7: The cxgb4 drivers will enable the PCIe Capability Device Control[Relaxed Ordering Enable] in PCI Probe() routine, this will break our current solution for some platform which has problematic when enable the relaxed ordering attribute. According to the latest recommendations, remove the enable_pcie_relaxed_ordering(), although it could not cover the Peer-to-Peer scene, but we agree to leave this problem until we really trigger it.

Make this patch set base on 4.12 release version.

v8: Change the second patch title and description to make it more reasonable, add the acked-by from Alex and Ashok.

Add a new patch to enable the Relaxed Ordering Attribute for cxgb4vf driver.

Make this patch set base on 4.13-rc2.

v9: The document (https://software.intel.com/sites/default/files/managed/9e/ bc/64-ia-32-architectures-optimization-manual.pdf) indicate that the Xeon processors based on Broadwell/Haswell microarchitecture has the problem with Relaxed Ordering Attribute enabled, so add the whole list Device ID from Intel to the patch.

v10: Significant rework based on Bjorn's feedback, reorganize the first 2 patches, now the Intel and AMD erratum soc has been divided to the different patches, rename the pcie_relaxed_ordering_supported() to pcie_relaxed_ordering_enabled(), and no need to check every intervening switch except the root ports, update some commits.

Casey Leedom (2): net/cxgb4: Use new PCI_DEV_FLAGS_NO_RELAXED_ORDERING flag net/cxgb4vf: Use new PCI_DEV_FLAGS_NO_RELAXED_ORDERING flag